Gum disease, such as gingivitis and/or periodontitis, gives rise to acute and chronic gum inflammation in the oral cavity. “Gingivitis” is the milder form of the disease. Symptoms of gingivitis may include: gingival bleeding; and redness, swollen, or tender gums. If left untreated, gingivitis can advance to “periodontitis”. With periodontitis, gums pull away from the teeth and form spaces called “periodontal pockets” that can become infected by pathogenic bacteria. The bacteria are present on the tooth root surfaces as biofilms. The bacteria in the biofilms can attack the gingival and underlying alveolar bone supporting teeth. These attacks can cause major damage to the soft tissue and bone that support teeth. In the later stage of gum disease (i.e., “advanced periodontitis”), more serious problems of loosening of teeth and eventual tooth loss can occur.
Some commercially available oral care compositions aim, principally, at alleviating one or more symptoms of the earlier stage of gum disease (i.e., gingivitis), which includes: relief of red, swollen, or tender gums; and/or stem gum bleeding. Typically, these compositions claim benefits such as, “gum care”, “oral care”, “oral health”, “dental care,” or “dental health” to users. An example of such a composition is “Colgate® Total” toothpaste, which they claim to “help reduce the first stage of gum disease”, which is defined as “gingivitis, or bleeding gums” (see http://www.colgatetotal.com/total-benefits/whole-mouth-health/gingivitis-control). To help distinguish the benefits of the commercially available oral care compositions versus the present invention, the inventors herein refer to the aforementioned benefits of these commercially available oral care compositions collectively as “Gum Care”. This is because these commercially available oral care compositions have been formulated primarily to care for the gums and relieve the symptoms (e.g., gum bleeding; and/or redness, swelling, or tender gums) associated with the earlier stage of gum disease (i.e., gingivitis).
However, there is a need to provide overall “Gum Health” benefits, which as used herein, is a broader term and is intended to encompass at least some of the aforementioned Gum Care benefits, as well as providing additional anti-bacterial benefits to mitigate the harmful effects of bacteria as it relates to gum disease, including gingivitis, periodontitis, or both.
There is at least one of several drawbacks to the above described conventional approaches. Firstly, these commercially available oral care compositions may promote Gum Care, but they do not go far enough to also promote Gum Health. In fact, these commercially available oral care compositions generally fail to provide any significant anti-bacterial effects in addition to the Gum Care benefits (e.g., anti-bleeding and/or anti-swelling). This is a problem because if the bacteria in the biofilms are not controlled, they can then increase the size of the periodontal pockets leading to periodontitis. Secondly, Gum Health may correlate to overall body health. In other words, an individual's Gum Health can be an indicator of the person's overall body health. Studies suggest that the risk of developing any one (or more) of these potential life-threatening conditions such as, for example, heart disease and stroke, diabetes, kidney disease, preterm birth, and/or osteoporosis, may increase as overall Gum Health decreases (see U.S. Pat. No. 6,846,478; Doyle, M. J.; & U.S. Pat. No. 8,283,135; Doyle, M. J.). Thus, it is desirable to improve overall Gum Health, not just Gum Care, in order to ensure better overall body health.
Stannous salts, such as stannous fluoride has been used in oral care compositions as to provide Gum Health benefit, including antimicrobial effect, reduced gingivitis, decreasing progression to periodontal disease, reductions in dentinal hypersensitivity, and reduced coronal and root dental caries and erosion. However, there are disadvantages for conventional stannous containing compositions. A first side effect routinely encountered during use of effective stannous fluoride formulations is unacceptable formulation astringency. secondly, formulating stannous ions stably also presents a challenge as the tin (II) ion is both prone to oxidation towards tin (IV) and to precipitate from aqueous solution as stannous hydroxide. Thirdly, stannous salts tend to discolor the oral care compositions, turning them yellow to dark brown. In order to overcome this problem, those conventional stannous containing compositions further comprising additional components such as, for example, TiO2, folic acid or flavor mixtures (e.g., methyl salicylate, menthol, eugenol and cineol) to prevent the above-described discoloration in storage without significantly diminishing the stability and activity of stannous salts. Therefore, it is desired to simplify formulations and processing steps to provide cost effective and efficacious toothpaste and other oral care formulations.
Oral care compositions containing stannous salts and zinc ion source have been described. Soluble zinc salts, such as zinc citrate, have been used in dentifrice compositions, but have several disadvantages. Free zinc ions may react with fluoride ions to produce zinc fluoride, which is insoluble and so reduces the availability of both the zinc and the fluoride. Moreover, zinc ions in solution impart an unpleasant, astringent mouthfeel, so formulations that provide effective levels of zinc, and also have acceptable organoleptic properties, have been difficult to achieve. Finally, the zinc ions will react with anionic surfactants such as sodium lauryl sulfate, thus interfering with foaming and cleaning. Therefore, there is a need to optimize the usage of zinc in the formulation.
Therefore, there is a continuous need to provide an oral care composition that provides Gum Health benefits to users, or at least provide better associated Gum Health benefits (e.g., gingival wound healing and anti-bacterial benefits) than those compositions that are commercially available.